anything location-based that you don't need to be a programmer to figure out

the ability to control the experience of my business profile (portability and design will also set Twitter apart from the rigid Facebook)

It's early days, and many Googlers participating in the network actively, as well as their teams, are collecting feedback from users as quickly as it comes. They also designed an intuitive way of signaling what the comment/request is about by letting you highlight that part of the page.

Rather than taking the approach of divining what will be, let's take a look at what they have already addressed off my Twitter wish list above:

speed and reliability -- while it was better when fewer people were kicking its tires, so to speak, it is still holding its own

powerful search feature to identify industry/interest -- it's Google, I would be shocked if search were left out of this. I put in "financial services" in the search box, and it served me with Google Profiles that match those keywords. Once again, this makes it harder for Google Apps customers. As for search in general, it seems to favor information that is contained in Google Profiles vs. in streams/conversations. I submitted feedback about this

better ways to create lists for filtering content (than manually) -- right now, everyone is busy building circles and labeling them. Will Google tag and learn from those? This is another piece of feedback I submitted

bulk subscriber management options -- circles take care of this in part. You have the ability to move people around in them easily, and filter streams based upon how you organized them. I still haven't found a way to filter by two circles without creating a third circle that combines the people in the first two. I should be able to check more than one on the sidebar

spam filters for DMs -- this is something I haven't come across yet. I have sent a couple of test messages directly to people, and I have not received any directly to me

location-based has been taken care of -- you can add the location when you send a message (see the symbol, a key, you can select)

ability to control the experience of my business profile -- portability and design already set Google Profile apart. I'm hoping the team will address the ability of Google Apps customers to have business profiles as well.

What other useful network features that are lacking in Twitter and Facebook would you like to see the next social network address? This is valid whether you're testing Google+ or not.